Answers

Best Answer: "Polly want a cracker" is a common saying to parrots, often used in training a parrot to speak.

One of the earliest uses of the phrase is in a fake advertisement from the mock newspaper the Bunkum Flag-Staff and Independent Echo published in 1849 in The Knickerbocker magazine. It starts, “For sale, a Poll Parrot, cheap. He says a remarkable variety of words and phrases, cries, ‘Fire! fire!; and ‘You rascal!’ and ‘Polly want a cracker,’ and would not be parted with, but having been brought up with a sea-captain he is profane and swears too much.”

The phrase also appears in a cartoon from The John-Donkey, July 29, 1848, p. 47, via Proquest American Periodical Series. The John-Donkey was a short-lived humorous and satirical magazine edited by Thomas Dunn English.

It was popularized by the 1883 Robert Lewis Stevenson novel "Treasure Island," as played out in the following scene:
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CUT-THROAT COLIN: Arrrhh! I had a pet parrot once!

SKINT (With a parrot on his shoulder): Oh, really?

CUT-THROAT COLIN: Arr! it used to lay square eggs!

SKINT: Amazin'! Did it ever speak?

CUT-THROAT COLIN: Oh, arrh, - what it usually said were - 'Ouch!'

Parrot treats this remark with silent contempt.

POOP DECK PETE: (To Captain Skint) Does your parrot bite?

SKINT: Oh, no, my parrot definitely doesn't bite!

POOP DECK PETE: Oh, good, (to parrot) Who's a pretty little Polly then? Polly want a cracker? (Reaches out to tickle parrot patronizingly under the chin. The parrot gives him a fierce nip on the fingers)

POOP DECK PETE: (Sucking damaged fingers and leaping about in pain) I thought you said your parrot didn't bite!

SKINT: It doesn't--but that's not my parrot.

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While it's likely not the first use of the expression, Treasue Island has popularized many other "pirate" sayings, such as "yo ho ho and a bottle of rum" or "sixteen men on a dead man's chest" (both of which it invented).

From very early, it was common practice to name parrots (or more specifically, macaws) Polly, first attested by the 1611 play "Volpone" by Ben Johnson, in which he wrote of a parrot named Pol. At that time, parrots were a new thing in the world, except to Incans and Mayans, as was the decision on proper names. Thus began the trend of naming parrots Pol, Poll, Polly, or Polly-O.

Why these names? Ben Johnson was born in Westminster, but claims to be of a Border family (i.e., the border of England and Scotland). Pol is a Scottish variant of Paul, and Ben is credited with first naming a parrot Pol, linking the naming of Parrots to "Paul" as opposed to "Polly" (a pet name for "Molly," which is a variation of Mary).

Poll is also British slang for a talkative person, explaining why a parrot (who can "talk") was given the name Pol by a British author.

An old nursery rhyme went:

Little Poll Parrot
Sat in his garret
Eating toast and tea;
A little brown mouse
Jumped into the house,
And stole it all away.

This rhyme could have been another source for the widespread use of Polly as a parrot's name.

Parrots come from areas that were first settled by the Spanish. The Spanish word for chicken is pollo. Natives adopted the word "pollo" / "Polly" for parrots, then Europeans readopted the term as a pet name.

The phrase "Polly want a cracker?" became popular through the cartoon, "I Wanna Be a Sailor" (1937), which you can watch here: